This invention relates to telephone answering devices, and in particular, automatic screening devices used with telephone answering devices to screen incoming calls from remote telephone sets.
As shown in FIG. 1, a telephone answering device 20 is commonly used in conjunction with one or more telephone sets 30, 40, 50 on a single external telephone line 10 to receive incoming calls. Answering device 20 is typically placed in series with and located in the same unit as or near one of the telephone sets, e.g., telephone set 30. Telephone sets 30, 40, 50 may be located in separate locations, e.g., different rooms of a house.
When a call is received on telephone line 10, all of the telephone sets 30, 40, 50 connected to line 10 ring for a short period prior to actuation of answering device 20. If the call is not answered by picking up one of the telephone sets 30, 40, 50 during the ringing period, answering device 20 connects to line 10, plays a recorded instruction or outgoing message directing the caller to leave a message for the called party and records the caller's message for subsequent retrieval. The caller's message may be broadcast by answering device 20 as it is being recorded.
For one type of conventional answering device, if any of the telephone sets 30, 40, 50 is picked up during operation of the answering device, operation of the answering device is interrupted, and the called party may speak with the caller via the telephone set. The called party may thus "screen" incoming calls by listening to the caller's message as it is being recorded and broadcast by the answering device. If the called party does not desire to speak with the caller, he simply does not pick up any of telephone sets 30, 40, 50 and allows answering device 20 to complete the recording of the caller's message for retrieval at a later time. But this type of call screening is effective only where the called party is in proximity to answering device 20 to listen to the caller's message as it is being recorded and broadcast.
In a known device for putting a call on "hold", an apparatus is connected to the telephone line in series with a telephone set which puts incoming calls on hold. After the called party has picked up the handset of the telephone set, he can depress a switch on the apparatus that disables the microphone in the telephone set. The called party may then listen to the communications on the line, although the caller cannot hear any sounds originating from the telephone set of the called party. To resume the conversation with the caller, the called party again depresses the switch, which enables the microphone in the telephone set. This known device is not designed to work in conjunction with a telephone answering device.